VW Passat Hybrid Cruise Control Malfunction Fix Guide

As someone with some experience working on hybrid vehicles, I encountered a very similar issue with my VW Golf GTE Hybrid 2021. The steering wheel controls and cruise control became non-functional, with error messages appearing in the display cluster. After checking the fuse box myself (which showed no visible issues), I took it to a workshop. They diagnosed a faulty system connection between the steering wheel module and the main control unit. The issue was traced to a loose cable connection that had developed over time, causing intermittent malfunctions in the cruise control system. The repair involved reconnecting and securing the cable properly, plus a system reset to clear the stored error codes. Total cost was 95€ for diagnostics and repair work. Since then, the cruise control has worked flawlessly. To provide more specific advice for your case, could you share: Are there any specific error codes showing up? Does the malfunction occur all the time or intermittently? Have you noticed any other electrical issues, especially with other steering wheel controls? When did the problem first start? These details would help determine if your issue matches what I experienced or if it might be something different.

I took it back to the workshop yesterday for diagnostics after my latest service at 65390km. They found error code P0638 related to the throttle body control circuit and additional codes pointing to the steering wheel control module. The issue occurs constantly now, though it started intermittently about 3 weeks ago. The technicians mentioned possible water damage to the control module connections, but wanted to order parts before confirming. Other steering wheel functions like volume and menu controls still work normally. Before spending money on major repairs, I wanted to check if anyone successfully fixed similar issues with just cleaning or reconnecting components. The car electronics otherwise function perfectly, including all hybrid system displays. Just hoping this cruise control problem has a simpler fix than replacing the entire control module.

Thanks for those details. Having gone through a similar situation with my VW Golf GTE Hybrid, the error code P0638 linked to the throttle body control circuit sounds more serious than my initial cable connection issue. Since your other steering wheel controls are working, this points more toward a throttle body system problem rather than the steering wheel module I initially suspected. The throttle body plays a crucial role in cruise control operation, and water damage to its connections can definitely trigger these symptoms. In my case, after the initial fix I mentioned, similar issues returned months later. The workshop found the throttle body itself had become corroded internally, causing erratic signals. A thorough cleaning of the throttle body connections provided temporary relief, but ultimately, replacement was necessary for a permanent fix. The repair cost was 450€ including diagnostics and parts. Before authorizing expensive repairs, request that they: 1. Clean and inspect the throttle body connections 2. Check the wiring harness for any signs of water damage 3. Test the throttle position sensor signals If cleaning doesnt resolve the issue, replacing the throttle body is likely necessary for reliable cruise control operation. With similar mileage on our hybrid systems, these components can show wear around this time.

The issue seems to be getting clearer. Thanks for sharing your experiences. Based on the comments about water damage and the P0638 code related to the throttle body control circuit, I will ask the workshop to follow those inspection steps before proceeding with parts replacement. The constant nature of the malfunction now versus the intermittent issues three weeks ago suggests the problem is getting worse. Since other steering wheel functions still work, focusing on the throttle body system makes more sense than replacing the entire control module. I will have them thoroughly clean and inspect the throttle body connections first. If that doesnt fix the faulty system, at least the 450€ replacement cost you mentioned gives me a reasonable estimate of what to expect. The cruise control is essential for my longer drives, so a proper fix is worth the investment rather than continuing to troubleshoot. Will update once the workshop completes their inspection and cleaning process. Hopefully, they can identify if water damage is truly the root cause before ordering replacement parts.